Generally, a serious patient such as a quadriplegic who is not able to move about freely spend most time of a day on lying on a bed or sitting on a wheelchair, with help of care workers or family dependents. As the old population has been increasing, the population lying on beds because of old age or dementia has been increasing.
However, overpressure is locally applied to a patient lying or sitting for a long time in the back, bottom touching a surface of a bed or wheelchair. A blockage of capillary blockage is continued by such overpressure constantly and repeatedly applied to the local part of the patient body. Accordingly, blood fails to flow through a skin tissue of the body part only to generate bedsores.
The tension applied to the location of the bedsore and the time of the tension activation can be important in this case. In an early stage, there is no damage to the skin tissue but discoloration on the location. As the bedsore is advanced, a sore starts to occur in a skin epidermal tissue and the inner skin under the skin epidermal tissue happens to be damaged. Even in a severe case, the bedsore can damage to the muscle or osseous tissue.
Moreover, such the patient might have a great pain enough to destroy the quality of the life. First of all, in case the bedsore happens to the patient unable to move freely, the recovery speed is slow according to characteristics of the elderly patient or patient unable to move freely and it might be quite difficult for such the patient to recover from the bedsore and the sore is subject to aggravation. There may be quite social costs of the economical loss required by the expense of treating the bedsore and of the death of the patient.
To solve such problem, there are many hospitals using electric-movable beds recently.
Such an electric-movable bed 10 can have a back supporting part 12 supporting the human back and a leg supporting part 14, of which angles are adjusted in an electric type to change the patient's position easily to make easy to take care of the patient advantageously.
However, every patient has a different body type and the locations of the bottom and knee can be differentiated according to the body type. In a conventional electric-movable bed, a rotating portion is fixed. Accordingly, the patient might have a wrong position if the patient's body type is not fitted to the electric-movable bed, only to cause the patient's uncomfortable feeling. Also, if such a wrong position is repeated for a long time, musculoskeletal system disorder might be caused. As the conventional electric-movable bed has no function of changing the patient body type periodically and automatically, such that the load and shear force applied to a specific skin location only to generate bedsores disadvantageously.
Moreover, to prevent the bedsores from occurring in the patient lying on the bed, the angle of the supporting part provided in the electric-movable bed is changed on a regular cycle. Even when changing the position of the patient with the change of the angle on the regular cycle, such a position change cycle might be applied uniformly, not be optimized according to the patient's sex, age, weight and other personal characteristics of the patient. Accordingly, optimized position change cycle for each patient cannot be provided disadvantageously.